Universal Serial Bus (USB) connectors are well-known and in widespread use, in particular, in association with peripheral devices of with computer systems. Specifications for USB connectors are described in full detail in Universal Serial Bus Specification, which can be found at www.usb.org and the disclosure of which is hereby expressly incorporated by reference into this specification. Chapter 6 of the Universal Serial Bus Specification document relates to mechanical features of USB connectors and cables.
USB connectors have many desirable features and advantages as compared to predecessor connectors. A disadvantage, however, is a relatively low resistance to unintended disconnection due to incidental axial pull-out forces, e.g., when a cable is inadvertently pulled or snagged. In many environments, unintended disconnection of a USB connector is a mere nuisance, while in other applications, unintended cable disconnection can have more serious consequences.
This susceptibility of a USB connector to unintended disconnection due to axial pull-out force is associated with both Type A (Host) and Type B (Device or Slave) connectors. FIGS. 1A, 1B and 1C illustrate a conventional USB Type B connector 10 located at a distal end of a USB cable 12. The connector 10 is a male connector adapted to mate with a female USB Type B connector 14 (FIG. 1D) as is well-known in the art. The female connector 14 is connected to a housing H and comprises an inner plug portion 14p located within a recess 14r that is bounded by a peripheral edge 14e of the housing H so that a space 14s is defined between the plug portion 14p and the edge 14e. The inner plug portion 14p, itself, comprises a non-symmetric hexagonal receiver 14p1 and a rectangular stud 14p2. The receiver 14p1 is adapted to receive the mating hexagonal male plug portion 22 of the male connector 10, while the rectangular stud 14p2 is received inside the male plug portion 22 of the connector 10.
The male USB Type B connector 10 comprises a polymer body portion 20 and metallic male plug portion 22 that projects outwardly from the body portion 20. The body portion 20, itself, comprises a main portion 20a and a cable interface portion 20b that joins the main portion 20a to the cable 12. The main portion 20a is enlarged relative to both the cable interface portion 20b and the metallic plug portion 22 and, as such, the body portion 20 further comprises inner and outer transverse shoulders 20i, 20t that join the main portion 20a to the cable interface 20b and metallic plug portion 22, respectively.
FIG. 1E illustrates the conventional male USB Type B connector 10 and a conventional device M, e.g., an industrial automation module. The device M comprises a female Type B USB connector 14. The male Type B USB connector 10 is adapted to be mated with the female connector 14. Except for a friction fit between the metallic plug portion 22 of the connector 10 and the female plug portion 14p (FIG. 1D) of the female connector 14, there is no structure for locking the male Type B USB connector 10 to the female Type B USB connector 14. As noted, the connector 10 is thus susceptible to undesired disconnection in response to incidental axial pull-out force as can occur, e.g., when the cable 12 is pulled for any reason such as during cleaning, maintenance, movement of related components, entanglement with moving structures, etc.